CN112271219A - A kind of power diode chip mesa modeling method - Google Patents
A kind of power diode chip mesa modeling method Download PDFInfo
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- CN112271219A CN112271219A CN202011173277.6A CN202011173277A CN112271219A CN 112271219 A CN112271219 A CN 112271219A CN 202011173277 A CN202011173277 A CN 202011173277A CN 112271219 A CN112271219 A CN 112271219A
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10D8/00—Diodes
- H10D8/422—PN diodes having the PN junctions in mesas
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- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
- H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
- H01L21/30604—Chemical etching
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
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- H10D8/00—Diodes
- H10D8/01—Manufacture or treatment
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Abstract
本发明涉及一种功率二极管芯片台面造型方法，它将一定数量的已经扩散和烧结电极的芯片放入可转动滚筒内，然后再将滚筒和芯片一起放入有混合腐蚀液的腐蚀液槽中滚动腐蚀；所述混合腐蚀液由硝酸、氢氟酸、硫酸、冰乙酸依次按9：9：12：4体积比混合组成，其酸液浓度分别为硝酸65‑68%，氢氟酸40%，硫酸98%，冰乙酸98%；所述混合腐蚀液温度始终为零下10℃至零下20℃。本发明可同时批量完成芯片台面造型，其生产效率比机械研磨方法提高10倍，并且芯片台面造型一致性好。
The invention relates to a table top modeling method for power diode chips, which puts a certain number of chips that have diffused and sintered electrodes into a rotatable drum, and then puts the drum and the chips into an etching solution tank with mixed etching solution for rolling Corrosion; the mixed corrosion solution is composed of nitric acid, hydrofluoric acid, sulfuric acid, and glacial acetic acid in a volume ratio of 9:9:12:4, and the acid concentration is 65-68% of nitric acid and 40% of hydrofluoric acid, respectively. Sulfuric acid 98%, glacial acetic acid 98%; the temperature of the mixed corrosion liquid is always minus 10 ℃ to minus 20 ℃. The invention can simultaneously complete the chip table top modeling in batches, the production efficiency is increased by 10 times compared with the mechanical grinding method, and the chip table top modeling consistency is good.
Description
Technical Field
The invention relates to a method for molding a power diode chip mesa, and belongs to the technical field of semiconductor device manufacturing.
Background
The mesa modeling and processing of the power diode chip are important links in the production of power semiconductor devices, namely the terminal processing of PN junctions, and the purpose is to form a certain oblique angle at the PN junction terminal by technical means, so as to reduce the surface electric field and form good chip voltage resistance. The conventional power diode chip mesa molding is to grind an oblique angle at the edge terminal of a silicon wafer by mechanical grinding to form a mesa, then sinter the cathode and anode electrodes, and remove the mesa oxide layer and surface contaminants by chemical corrosion to form a smooth and pollution-free mesa surface, and the process is shown in fig. 1-4. In the process of mass production, the conventional mechanical grinding method is used for table top modeling, the production efficiency is very low, manual operation is needed, the labor cost is high, the influence of human factors is large, and the product consistency is poor.
Disclosure of Invention
The invention mainly aims to solve the problem of low efficiency of the conventional mesa modeling technology, and provides a mesa modeling method of a power diode chip with higher production efficiency.
The technical scheme adopted by the invention is that the table-board modeling method of the power diode chip is characterized by comprising the following steps of:
(1) preparing a power diode chip with diffused and sintered cathode and anode electrodes;
(2) putting a certain number of the chips into a rotatable roller, and then putting the roller and the chips into a corrosive liquid tank with mixed corrosive liquid; the chip rolls and corrodes in the mixed corrosive liquid along with the roller, the rotating speed of the roller is 8-10 r/min, and the corrosion time is 20-30 minutes; the mixed corrosive liquid is prepared by sequentially mixing nitric acid, hydrofluoric acid, sulfuric acid and glacial acetic acid according to the weight ratio of 9: 9: 12: 4 volume ratio, wherein the acid liquor concentration is 65-68% of nitric acid, 40% of hydrofluoric acid, 98% of sulfuric acid and 98% of glacial acetic acid; the temperature of the mixed corrosive liquid is always between 10 ℃ below zero and 20 ℃ below zero;
(3) after the chip is corroded in a rolling mode for a preset time, the chip is transferred into a cleaning water tank to be cleaned, then the chip is taken out, water is drained, and the chip is placed into an oven to be dried, wherein the drying temperature is 160-180 ℃.
Further, the rolling corrosion time of the chip is 23-26 minutes; the temperature of the mixed corrosive liquid is always below-15 ℃. Therefore, the molding efficiency of the chip mesa is higher.
Further, after the chip is corroded in a rolling mode for a preset time, the roller and the chip are transferred into a cleaning water tank for rolling cleaning, the rotating speed of the roller is 8-10 rpm, after the chip is cleaned, the chip is taken out, water is drained, and the chip is placed into an oven for drying, wherein the drying temperature is 160-180 ℃. Therefore, the table top of the chip has better modeling consistency.
The beneficial technical effects of the invention are as follows: by putting a certain number of power diode chips into the mixed corrosive liquid for rolling corrosion, the table-board molding of the chips can be simultaneously completed in batches, the production efficiency is improved by 10 times compared with that of a mechanical grinding method, and the consistency of the table-board molding of the chips is good.
Drawings
Fig. 1 is an enlarged schematic view of a cross-sectional structure of a silicon wafer after conventional diffusion cutting.
FIG. 2 is an enlarged schematic view of a cross-sectional structure of a conventional mechanically polished silicon wafer.
FIG. 3 is an enlarged schematic view of a cross-sectional structure of a chip after sintering of a cathode and an anode in a conventional manner.
Fig. 4 is an enlarged schematic view of a cross-sectional structure of a chip after a conventional mesa formation etching process.
FIG. 5 is an enlarged schematic view of a cross-sectional structure of a conventional diffusion-cut silicon wafer.
FIG. 6 is an enlarged schematic view of the cross-sectional structure of the chip after sintering the cathode and anode electrodes according to the present invention.
FIG. 7 is an enlarged schematic view of the cross-sectional structure of the chip after the mesa etching formation is completed according to the present invention.
Detailed Description
The processing process of the invention is shown in fig. 5, fig. 6 and fig. 7, and the method for modeling the mesa of the power diode chip is characterized by comprising the following steps:
(1) preparing a power diode chip with diffused and sintered cathode and anode electrodes;
(2) putting a certain number of the chips into a rotatable roller, and then putting the roller and the chips into a corrosive liquid tank with mixed corrosive liquid; the chip rolls and corrodes in the mixed corrosive liquid along with the roller, the rotating speed of the roller is 8-10 r/min, and the corrosion time is 20-30 minutes; the mixed corrosive liquid is prepared by sequentially mixing nitric acid, hydrofluoric acid, sulfuric acid and glacial acetic acid according to the weight ratio of 9: 9: 12: 4, the acid liquor concentration is 65-68% of nitric acid, 40% of hydrofluoric acid, 98% of sulfuric acid and 98% of glacial acetic acid respectively; the temperature of the mixed corrosive liquid is always between 10 ℃ below zero and 20 ℃ below zero;
(3) after the chip is corroded in a rolling mode for a preset time, the chip is transferred into a cleaning water tank to be cleaned, then the chip is taken out, water is drained, and the chip is placed into an oven to be dried, wherein the drying temperature is 160-180 ℃.
In the present invention, it is preferable that the chip rolling etching time is 23 to 26 minutes; the temperature of the mixed corrosive liquid is always below-15 ℃. Therefore, the molding efficiency of the chip mesa is higher. The mixed corrosion liquid temperature can be cooled by an external refrigeration system.
In the invention, after the chip is corroded in a rolling way for a preset time, the roller and the chip are preferably transferred into a cleaning water tank together for rolling cleaning, the rotating speed of the roller is 8-10 r/min, after the cleaning is finished, the chip is taken out, the water is drained, and the chip is placed into an oven for drying, wherein the drying temperature is 160-180 ℃. Therefore, the table top of the chip has better modeling consistency. In the rolling cleaning process, the ultrasonic action is added, so that the cleaning effect is better, and the cleaning speed is higher. In addition, after the chip is corroded in a rolling mode for a preset time, the chip can be taken out and washed by clean water, and then the chip is placed into an oven to be dried.
In the process of the invention, the layers of the chip cross-sectional structures shown in fig. 6 and 7 are respectively cathode solder, cathode liner, silicon chip, anode liner and anode solder from top to bottom, wherein the silicon chip shown in fig. 6 is not mechanically ground. In the conventional method, the layers of the chip cross-sectional structures shown in fig. 3 and 4 are respectively cathode solder, a cathode gasket, a silicon wafer, an anode gasket and anode solder from top to bottom, wherein the silicon wafer shown in fig. 3 is mechanically subjected to corner grinding.
The roller is provided with an opening and can be closed, and the periphery of the side wall of the roller is uniformly distributed with small through holes, so that after the roller is placed in a corrosion liquid groove with mixed corrosion liquid, the mixed corrosion liquid can flow into the roller through the small through holes distributed on the side wall of the roller, and a chip placed in the roller can be corroded in the mixed corrosion liquid. The roller is driven by a machine to rotate in the mixed corrosive liquid. The corrosion liquid in the groove is cooled to a preset low-temperature state by a refrigerating system in advance, and the refrigerating system continuously works in the machining process.
The mixed corrosive liquid is set at low temperature in the invention, because in the chip structure, the silicon chip contains lead, tin, molybdenum, iron, nickel and other metals besides the semiconductor material silicon. In the conventional general etching process, the above-mentioned metal material is also severely corroded in addition to silicon. These corroded metals can adversely contaminate the pressure-resistant mesa of the chip, affecting the stability of the chip. At low temperature, the mixed corrosive acid liquid can corrode other metals very slowly or basically not, so that the impurity content in the corrosive liquid is greatly reduced, the pollution degree of the chip is also greatly reduced, and the performance stability of the chip can be improved. The corrosion speed of the low-temperature mixed corrosion acid liquid on the silicon is also reduced, but the reduction is less compared with the corrosion speed of other metals, and the corrosion effect can be achieved by properly prolonging the corrosion time.
According to the chip after the cathode and the anode are sintered, the diameter of the anode gasket of the chip is 2mm larger than that of the silicon wafer, and the diameter of the gasket on the cathode is slightly smaller than that of the silicon wafer, so that the reliability of the chip with the structure is better. Since the silicon chip size in the chip is made larger as possible on a fixed-size anode substrate to facilitate the chip current capacity. However, the silicon wafer is too large in diameter, so that the silicon wafer is too close to the bottom edge of the anode gasket, the silicon wafer is easy to be damaged in use, and therefore, a proper silicon wafer size needs to be selected. And the size of the upper cathode lining is set to be slightly smaller than the size of the silicon wafer according to the size of the silicon wafer, so that the coating of the protective adhesive is facilitated.
The invention puts a certain amount of power diode chips into the mixed corrosive liquid in batch for rolling corrosion, and completes the table top modeling of the chips in batch by a corrosion method, and the production efficiency is very high. The table-board model of the chip is produced by adopting the traditional mechanical hair grinding method, each person generally processes 2000 pieces each day, while the method of the invention can achieve 20000 pieces each day, and the efficiency is improved by 10 times.
Claims (3)
1. A power diode chip mesa modeling method is characterized by comprising the following steps:
(1) preparing a power diode chip with diffused and sintered cathode and anode electrodes;
(2) putting a certain number of the chips into a rotatable roller, and then putting the roller and the chips into a corrosive liquid tank with mixed corrosive liquid; the chip rolls and corrodes in the mixed corrosive liquid along with the roller, the rotating speed of the roller is 8-10 r/min, and the corrosion time is 20-30 minutes; the mixed corrosive liquid is prepared by sequentially mixing nitric acid, hydrofluoric acid, sulfuric acid and glacial acetic acid according to the weight ratio of 9: 9: 12: 4 volume ratio, wherein the acid liquor concentration is 65-68% of nitric acid, 40% of hydrofluoric acid, 98% of sulfuric acid and 98% of acetic acid; the temperature of the mixed corrosive liquid is always between 10 ℃ below zero and 20 ℃ below zero;
(3) after the chip is corroded in a rolling mode for a preset time, the chip is transferred into a cleaning water tank to be cleaned, then the chip is taken out, water is drained, and the chip is placed into an oven to be dried, wherein the drying temperature is 160-180 ℃.
2. The method of claim 1, wherein the method comprises: the rolling corrosion time of the chip is 23-26 minutes; the temperature of the mixed corrosive liquid is always below-15 ℃.
3. The method of claim 1, wherein the method comprises: and after the chip is corroded in a rolling way for a preset time, transferring the roller and the chip into a cleaning water tank for rolling cleaning, wherein the rotating speed of the roller is 8-10 rpm, and drying the chip in an oven at 160-180 ℃.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202011173277.6A CN112271219A (en) | 2020-10-28 | 2020-10-28 | A kind of power diode chip mesa modeling method |
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| CN202011173277.6A CN112271219A (en) | 2020-10-28 | 2020-10-28 | A kind of power diode chip mesa modeling method |
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Citations (6)
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| US20090111245A1 (en) * | 2005-06-01 | 2009-04-30 | Shin-Etsu Handotai Co., Ltd. | Method for manufacturing bonded wafer |
| CN106024675A (en) * | 2016-05-13 | 2016-10-12 | 江苏佑风微电子有限公司 | Semiconductor silicon wafer corrosive liquid and corrosion method thereof |
| CN106024624A (en) * | 2016-07-23 | 2016-10-12 | 中国振华集团永光电子有限公司（国营第八七三厂） | Manufacturing method of highly-reliable anti-radiation transient voltage suppressing diode |
| CN108598180A (en) * | 2018-04-11 | 2018-09-28 | 浙江世菱电力电子有限公司 | A kind of rectifier diode and preparation method thereof |
| CN109616411A (en) * | 2018-11-29 | 2019-04-12 | 嘉兴柴薪科技有限公司 | A kind of glass passivation process for diode |
| CN111584363A (en) * | 2020-05-28 | 2020-08-25 | 山东芯诺电子科技股份有限公司 | Circular glass passivated diode rectifier chip for rotary rectifier and its production process |
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2020
- 2020-10-28 CN CN202011173277.6A patent/CN112271219A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20090111245A1 (en) * | 2005-06-01 | 2009-04-30 | Shin-Etsu Handotai Co., Ltd. | Method for manufacturing bonded wafer |
| CN106024675A (en) * | 2016-05-13 | 2016-10-12 | 江苏佑风微电子有限公司 | Semiconductor silicon wafer corrosive liquid and corrosion method thereof |
| CN106024624A (en) * | 2016-07-23 | 2016-10-12 | 中国振华集团永光电子有限公司（国营第八七三厂） | Manufacturing method of highly-reliable anti-radiation transient voltage suppressing diode |
| CN108598180A (en) * | 2018-04-11 | 2018-09-28 | 浙江世菱电力电子有限公司 | A kind of rectifier diode and preparation method thereof |
| CN109616411A (en) * | 2018-11-29 | 2019-04-12 | 嘉兴柴薪科技有限公司 | A kind of glass passivation process for diode |
| CN111584363A (en) * | 2020-05-28 | 2020-08-25 | 山东芯诺电子科技股份有限公司 | Circular glass passivated diode rectifier chip for rotary rectifier and its production process |
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